Plants, including turf-gasses, live in an often-hostile environment, where they are subject to many stressors including heat, cold, drought, flooding and attack by pests such as insects and fungi. Many different fungi infect grass roots, causing their death. These fungi include Basidiomycetes and Ascomycetes. The most visible are the fruiting bodies of Basidiomycetes, the well-known mushrooms and puffballs. The fungal infections they cause are often called fairy rings and mini-rings. Other Basidiomycetes cause an array of fungal diseases, including so-called rust, root rot, Rhizoctonia diseases of turf grass, stinking smut, and others. These fungi are more difficult to identify, because they rarely if ever have their fruiting stage, which is the diagnostic anatomical test for fungi. Currently even experts have difficulty identifying them, and the only secure way is to do genomic analysis. Nevertheless, all these fungi are typically given the generic name Rhizoctonia. The second major group of fungi is Ascomycetes, which are even less well characterized. They cause diseases such as anthracnose of turf grass, dollar spot of turf grass, (caused by Sclerotinia homoeocarpa), early blight of potato and tomato, and others.
The majority of plants, including turf grass, especially when under stress, such as frequent mowing, extreme temperatures, drought, flooding, etc., becomes prone to fungal infections. These are proving difficult and expensive to control. It has been shown that the dark green circles in turf grass fields are from fungi colonizing the soil, leaf litter, thatch, or emanating from buried wood products. These fungi can sometimes cause the development of spots, rings or arcs of deep green grass or circles of dead grass, which may vary in size.
The most common fungi affecting the most sensitive (and valuable) turf grass swards are mycelium fungi attacking golf greens and the most common means of control is by toxic chemical fungicides. For example, on golf greens, the main fungal infestations are the result of thatch-dwelling and/or thatch-utilizing mycelium fungi. As with the majority of agents that kill (for example, toxic chemical fungicides), the rapidly growing organisms (for example, fungal mycelium) typically develop resistance. This is happening, for example, with some of the main fungicides used on golf courses, such as TARTAN®, PROSTAR 70WG®, TRINITY®, INSIGNIA®, and others.
The bulk of the fungus-evoked damage to golf greens results from the activity of mycelium fungi which: a) live in and utilize the thatch layer as their major food source. Removal of the food source would deplete the nutrition available to the fungi, thus lessen their abundance and thus the severity of damage inflicted on the turf; b) kill the fungi by secreting toxins and poisons; and c) make the soil hydrophobic, thus lessening the ability of the plants to take up water and nutrients. Since these are all saprophytic fungi (i.e., they cannot colonize living plants, they must kill them first, hence getting rid of the toxins would lessen fungal ability to attack the plant roots.
There have been many approaches to solve the problem of fungal infections. Some of them involve thatch management efforts, including changing the soil pH, and core aerating to remove thatch and enhance its breakdown and to permit water and air movement. Other efforts include the use of pesticides, fumigation of infected turf areas, removing portions of the infected soil, and applying nitrogen to mask the symptoms of infection, by causing the rest of the lawn to green up. None of these previous methods have been shown to be completely effective or environmentally friendly.
As the public pushes for organic environmental solutions, turf managers have found it challenging to maintain visually-pleasing, healthy turf while being environmentally friendly. Brown patch, yellow patch, fairy ring, and compacted and hydrophobic soils challenge soil and turf management practices. Despite the desire to reduce fungal growth, there are no really effective biological products to protect turf against fungal infestations. It is desirable to make turf care effective and simple at the same time, by reducing fungal infestation and controlling the growth of fungi using biological methods, in an environmentally friendly manner. It would be advantageous to invent compositions and methods that overcome these deficiencies as well as improving plant health. The present invention addresses these and related needs.